A seat apparatus disclosed in JP 2003532577A is well known. Estimated lateral acceleration, which is supposed to be applied to an occupant seated on a seat when a vehicle is driven on a curve portion of a road, is estimated a relatively large distance before the vehicle is actually driven on the curve portion based on data of a current driving route obtained from a memorized road map and a current vehicle data which is projected onto the driving route. The estimated lateral acceleration is transmitted to a control unit and then to a processing block via a prediction filter, taking into account a filling pressure-related delay time of an adaptation system which is inherent in the system and an instantaneous vehicle speed which is outputted by a sensor. A CUP transmits a corresponding electrical control signal to a pressure regulating device which changes the filling pressure of right air cushions of a seat cushion and a seat back or left air cushions of the seat cushion and the seat back. Thus, when the vehicle is driven on the curve portion of the road, a pre-setting of the seat for lateral support is already completed, and the acceleration sensor is used only for adjusting the pre-setting of the seat in detail by using minimum inflation or venting of the air cushions provided at the right and the left of each of the seat cushion and the seat back.
Hence, the seat apparatus disclosed in JP 2003532577A preliminarily implements seat setting when adaptation of seat support for supporting the seated occupant is required, for example, when the vehicle is driven on the curve portion of the road, so that necessary changes of the seat setting are already completed when the adaptation of the seat support is started. In this way, delay time, inherent in any adaptation system, between actuation of the adaptation system and changing of the seat is offset.
In the seat apparatus disclosed in JP2003532577A, the seat setting for supporting the seated occupant from the lateral acceleration is completed so as to offset delay time between actuation of the adaptation system and changing of the seat, while the vehicle is driven on the curve portion of the road. However, the seat apparatus disclosed in JP2003532577A does not control to offset an error caused due to information on the curve portion and current location of the vehicle.
Additionally, in the seat apparatus disclosed in JP2003532577A, compressed air is adopted as a driving source for moving a side support of the seat. However, when an electric motor, whose responsiveness to drive the side support is quicker than responsiveness of the air-type driving source, is adopted as the driving source, a need may exists to offset the error occurred due to the information on the vehicle location and the curve.
A need exists for a seat apparatus which is not susceptible to the drawback mentioned above.